HI Alan,
I know what you are saying is true but I was not present during any of the testing of the crossovers during their development. I can either send the crossovers back and ask him for the results of each of those steps he first stated and which you have highlighted. This maybe the best course of action? I don't really want to criticize him for the way he carries out his job. I have managed to put myself in an awkward position here! But looking back I should have paid more attention to the mismatched MD500's. This needs to be rectified before I can move on.
Best Regards
Wayne
Last edited:
continued from #700
With regard to the above:
First paragraph - there is no "if he still had the necessary data" involved.
These re-builders/re-conditioners do not erase useful data they obtain from measuing samples of drivers.
They store it so as to refer to when the next case of restoration using the same driver presents - that is how they build their business.
I recommend you do not limit your request by qualifying it. Instead, ask directly:
"Please send me the Time Domain plot from the ...{as I previously described it},
and, please send me all the plots from measurements you made of the mid-domes and SEAS tweeters on the dummy baffle."
You paid for those, thus you are entitled to have copies.
I recommend you do this very soon, because your period of legal redress will be less effective the longer you leave this matter.
I recommend you do not buy the newly specified capacitor and inductor, because until you understand the audible anomolies of that crossover you will only be exchanging one problem for another.
Also, you should not have to BUY any substitute components - those should be offered in exchange for the ones which did not do the job that you asked for,
however leave that for now, because you will likely have a lot more to ask for exchange or refund for after you come to understand what has been done and that such has not been what you were told it would be.
Second paragraph - this plot shows a reduced dip in the midrange, but it is still an average of -3dB maximum, versus the average of -6dB maximum of the version you are listening to.
Neither are a "BBC dip".
A "BBC dip" is a dip of between -1dB <--> -2dB.
This allows for sample variation between drivers and Tolerance +/- variations of the crossover's components.
-3dB is too audible, and a loudspeaker measuring such would be rejected by the BBC. They have strict specifications.
-6dB would be completely unacceptable.
The term "BBC dip" is much misunderstood, and has been often mis-applied by Reviewers.
Some listeners do like a dip as much as -3dB, but very few other than some heavy-metal fans would tolerate a -6dB dip, and the heavy-metal fans prefer the dip to be centred on the 1kHz region.
Around 3.5kHz, where your dip is, there is a lot of Electric Guitar harmonics' spectrum which no metal lover wants to lose !
Audibility of dip, or notch, depends also on its bandwidth.
A narrow band, deep notch is not as audible as a wide band low dB dip.
-1dB can be clearly heard when bandwidth is 2 octaves or wider.
-3dB can be clearly heard when bandwidth is half-octave or wider.
-6dB can be clearly heard when bandwidth is quarter-octave or wider.
I have done these experiments.
Critical listeners can hear the dips of less than -1dB if wide enough bandwidth,
and they can hear the various -dBs I listed above in narrower bandwidths than the average of the general population.
You have exchanged a dip of about -5dB of about half-octave in one of your mid-domes for a -6dB dip of slightly wider than 1 octave in you non-notched dome,
and wider in your notched dome because the 4.5kHz notch is still there but only reduced a little in audibilty.
Better would have been to stay with what you had, because that 4.5kHz notch is less audible than what you have now.
The new "simulated" plot of SPL Mag shows evidence of the 5kHz region anomoly in the SEAS tweeter that I mentioned in another Post today.
This problem needs to be solved before you change anything,
thus you will need to see the actual measured plots of the SEAS tweeters on the dummy baffle, as made with no crossover filter attached.
Also, raising the level of the upper mids with those alternate components will also raise the audible level of the 4.5kHz notch in the dome that you do not have a full mid + treble SPL Mag plot for so that you can see that.
Third paragraph - Morel EM 1308 has outer diameter of 130mm.
Are you saying that the hole through the 66 baffle is wider than 130mm ?
or is it a rebate in the 66 baffle that is approx. 165mm dia. and a smaller dia. hole through the baffle ?
I know of one case of Scanspeak mid substituted into a 66 by Audio Components that was not a success,
however I can say no more about that because I think the matter may not yet be resolved, and I do not know at this time.
Scanspeak 10F/8424G00 is a cone midrange. It is open backed, thus will require a small enclosure be installed behind it within the 66.
This will have to be a carefully chosen size, and suitably damped.
Such is not as easy to do as it may seem, similar to what you have now heard with your crossover.
Also, its outer diameter is 97.5mm only.
{It requires a 78.5 <--> 79mm dia. hole through the baffle.}
Also, it will require a different crossover, thus more cost to design.
Fourth paragraph - there are NO "newer and more technically advanced" inductors of the types suitable for use in crossovers !
ALL information about inductors has been know for a very long time.
These are not as difficult to manufacture as capacitors and resistors.
They are simply wire wound as a coil around a former, which can have air in its centre or any solid material.
Inductors were highly developed during the development of Radio broadcast an reception, because they were absolutely critical to that function being possible.
They were further very much developed for Military and Aerospace applications.
Jantzen's P-core is not new. It is application of a known material which Jantzen buy from another manufacturer.
Jantzen own only the Trademark they use for it.
The ONLY improvement about inductors is that with modern machinery they can be wound more cheaply, thus better quality inductors are cheaper now than years ago when hand-tension had to be applied along with hand-guiding of the wire feed.
If, and I do mean "if", there is any compromise in the Celestion inductors, it will be only that they may not be wound as tightly as current best possible,
but that is not necessarily a problem with audible consequences ... and you own four 2.2mH inductors you can chose the best two from if necessary.
The 2.2mH inductor in the mids' filter needs between 1 <--> 1.5 ohm of resistance, or you will have "shouty" sound there regardless of whatever else you may apply,
other than a 1 ohm resistor in Series with your new 2.2mH inductor !
This is ridiculous - you have spent money on a new component that has caused worse sound, instead of on new Polypropylene caps in the bass filter which would have caused better sound.
As you stated "newer and more technically advanced" - those new electrolytic caps are barely more advanced than the old ones.
They are simply new, thus not deteriorated in performance like the old ones, BUT as with ALL electro caps, they will deteriorate over time to poor sound, and the poly caps won't !
Also, the Dielectric Absorption is still there - because that is an unavoidable feature of ALL electro caps ... it cannot be designed out, whereas the polypropylene caps do not have D.A.
... and D.A. is quite audible, even in the low midrange and bass, but you have not heard the full difference because you did not insist on poly caps there.
The capacitor in Parallel with the mid-dome also needs some resistance in Series with it to reduce the "shouty" colouration.
{All components in a bandpass filter interact with each other and with the driver and cause additional effects than simply filtering at each end of the specified bandwidth.}
There is NO "technically advanced" aspect of the expensive Jantzen Silver Z-caps over the moderately priced Jantzen Superior Z-caps.
There is only a very small audible difference, and that is because there is NO perfect capacitor.
What you have paid for is expensive internal materials which cause the sound to be slightly different - slightly - not anywhere near the difference between a Standard Z-cap and a Cross-Cap and a Superior Z-cap, and very much smaller than the audible difference will be between Cross-caps or Solen or Axon poly caps versus electro caps in the bass filter.
Human hearing is most sensitive in the midrange, thus if "John" thinks that Cross-caps are adequate there, then they are adequate in the treble.
If you want to improve the treble you will have to improve the midrange, because human hearing automatically allocates its priority to the midrange.
When the midrange is improved, the bass and treble sound better, unless compromised by lower quality drivers or crossover components.
Get the midrange right as priority in allocating Budget, and then get the treble and bass to blend with the mids by using similar quality components.
Jantzen Z-Superior in both mids and treble will cause greater coherence than Z-Silver in one and Cross-Cap in the other.
Ideally the bass should have the same capacitor model also, but that will be very expensive with Z-Superior, and for little audible gain over Cross-Cap there.
You have now missed the 20% discount sale on Sonicaps, for which you could have got Jantzen Z-Superior quality in slightly different sound for lower price, and available in a wider selection of values so that you could have bought the optimum cap values for those drivers without having to connect parallel pairs or triples of Z-Superior, as you will eventually realize you will have to do if you want better than Cross-Cap {which originally given your specification I thought you did}.
You could have used your existing 66 crossover for mids and treble with Sonicaps installed, and bought lower DCR Solen or Jantzen AIR core inductors for the bass filter to allow greater bass level and somewhat faster bass sound.
You can still do this.
If you do not receive the copies of the measurements you paid for, and an offer to exchange non-optimum choice, poorly advised, components for same total price better type allocation components for your purpose, then demand a refund for the crossovers and send them back,
BUT, do not decide about any values of capacitance and inductance till you see all the measurements that were done.
I recommend that you ask for the measurements first.
If those are not sent to you, then send the entire crossovers back and demand refund for the prices of the board and parts.
You are legally entitled to that {unless you have given away you rights as result of some peculiar agreement}.
I have to go now. This is taking a very long time, and I think it likely that I have not addressed all your concerns.
I can better do that if I can see all the measurements that you were told were made, because then you can see what I am describing.
{Most people trust there eyes more than their ears, but I don't.}
With regard to the above:
First paragraph - there is no "if he still had the necessary data" involved.
These re-builders/re-conditioners do not erase useful data they obtain from measuing samples of drivers.
They store it so as to refer to when the next case of restoration using the same driver presents - that is how they build their business.
I recommend you do not limit your request by qualifying it. Instead, ask directly:
"Please send me the Time Domain plot from the ...{as I previously described it},
and, please send me all the plots from measurements you made of the mid-domes and SEAS tweeters on the dummy baffle."
You paid for those, thus you are entitled to have copies.
I recommend you do this very soon, because your period of legal redress will be less effective the longer you leave this matter.
I recommend you do not buy the newly specified capacitor and inductor, because until you understand the audible anomolies of that crossover you will only be exchanging one problem for another.
Also, you should not have to BUY any substitute components - those should be offered in exchange for the ones which did not do the job that you asked for,
however leave that for now, because you will likely have a lot more to ask for exchange or refund for after you come to understand what has been done and that such has not been what you were told it would be.
Second paragraph - this plot shows a reduced dip in the midrange, but it is still an average of -3dB maximum, versus the average of -6dB maximum of the version you are listening to.
Neither are a "BBC dip".
A "BBC dip" is a dip of between -1dB <--> -2dB.
This allows for sample variation between drivers and Tolerance +/- variations of the crossover's components.
-3dB is too audible, and a loudspeaker measuring such would be rejected by the BBC. They have strict specifications.
-6dB would be completely unacceptable.
The term "BBC dip" is much misunderstood, and has been often mis-applied by Reviewers.
Some listeners do like a dip as much as -3dB, but very few other than some heavy-metal fans would tolerate a -6dB dip, and the heavy-metal fans prefer the dip to be centred on the 1kHz region.
Around 3.5kHz, where your dip is, there is a lot of Electric Guitar harmonics' spectrum which no metal lover wants to lose !
Audibility of dip, or notch, depends also on its bandwidth.
A narrow band, deep notch is not as audible as a wide band low dB dip.
-1dB can be clearly heard when bandwidth is 2 octaves or wider.
-3dB can be clearly heard when bandwidth is half-octave or wider.
-6dB can be clearly heard when bandwidth is quarter-octave or wider.
I have done these experiments.
Critical listeners can hear the dips of less than -1dB if wide enough bandwidth,
and they can hear the various -dBs I listed above in narrower bandwidths than the average of the general population.
You have exchanged a dip of about -5dB of about half-octave in one of your mid-domes for a -6dB dip of slightly wider than 1 octave in you non-notched dome,
and wider in your notched dome because the 4.5kHz notch is still there but only reduced a little in audibilty.
Better would have been to stay with what you had, because that 4.5kHz notch is less audible than what you have now.
The new "simulated" plot of SPL Mag shows evidence of the 5kHz region anomoly in the SEAS tweeter that I mentioned in another Post today.
This problem needs to be solved before you change anything,
thus you will need to see the actual measured plots of the SEAS tweeters on the dummy baffle, as made with no crossover filter attached.
Also, raising the level of the upper mids with those alternate components will also raise the audible level of the 4.5kHz notch in the dome that you do not have a full mid + treble SPL Mag plot for so that you can see that.
Third paragraph - Morel EM 1308 has outer diameter of 130mm.
Are you saying that the hole through the 66 baffle is wider than 130mm ?
or is it a rebate in the 66 baffle that is approx. 165mm dia. and a smaller dia. hole through the baffle ?
I know of one case of Scanspeak mid substituted into a 66 by Audio Components that was not a success,
however I can say no more about that because I think the matter may not yet be resolved, and I do not know at this time.
Scanspeak 10F/8424G00 is a cone midrange. It is open backed, thus will require a small enclosure be installed behind it within the 66.
This will have to be a carefully chosen size, and suitably damped.
Such is not as easy to do as it may seem, similar to what you have now heard with your crossover.
Also, its outer diameter is 97.5mm only.
{It requires a 78.5 <--> 79mm dia. hole through the baffle.}
Also, it will require a different crossover, thus more cost to design.
Fourth paragraph - there are NO "newer and more technically advanced" inductors of the types suitable for use in crossovers !
ALL information about inductors has been know for a very long time.
These are not as difficult to manufacture as capacitors and resistors.
They are simply wire wound as a coil around a former, which can have air in its centre or any solid material.
Inductors were highly developed during the development of Radio broadcast an reception, because they were absolutely critical to that function being possible.
They were further very much developed for Military and Aerospace applications.
Jantzen's P-core is not new. It is application of a known material which Jantzen buy from another manufacturer.
Jantzen own only the Trademark they use for it.
The ONLY improvement about inductors is that with modern machinery they can be wound more cheaply, thus better quality inductors are cheaper now than years ago when hand-tension had to be applied along with hand-guiding of the wire feed.
If, and I do mean "if", there is any compromise in the Celestion inductors, it will be only that they may not be wound as tightly as current best possible,
but that is not necessarily a problem with audible consequences ... and you own four 2.2mH inductors you can chose the best two from if necessary.
The 2.2mH inductor in the mids' filter needs between 1 <--> 1.5 ohm of resistance, or you will have "shouty" sound there regardless of whatever else you may apply,
other than a 1 ohm resistor in Series with your new 2.2mH inductor !
This is ridiculous - you have spent money on a new component that has caused worse sound, instead of on new Polypropylene caps in the bass filter which would have caused better sound.
As you stated "newer and more technically advanced" - those new electrolytic caps are barely more advanced than the old ones.
They are simply new, thus not deteriorated in performance like the old ones, BUT as with ALL electro caps, they will deteriorate over time to poor sound, and the poly caps won't !
Also, the Dielectric Absorption is still there - because that is an unavoidable feature of ALL electro caps ... it cannot be designed out, whereas the polypropylene caps do not have D.A.
... and D.A. is quite audible, even in the low midrange and bass, but you have not heard the full difference because you did not insist on poly caps there.
The capacitor in Parallel with the mid-dome also needs some resistance in Series with it to reduce the "shouty" colouration.
{All components in a bandpass filter interact with each other and with the driver and cause additional effects than simply filtering at each end of the specified bandwidth.}
There is NO "technically advanced" aspect of the expensive Jantzen Silver Z-caps over the moderately priced Jantzen Superior Z-caps.
There is only a very small audible difference, and that is because there is NO perfect capacitor.
What you have paid for is expensive internal materials which cause the sound to be slightly different - slightly - not anywhere near the difference between a Standard Z-cap and a Cross-Cap and a Superior Z-cap, and very much smaller than the audible difference will be between Cross-caps or Solen or Axon poly caps versus electro caps in the bass filter.
Human hearing is most sensitive in the midrange, thus if "John" thinks that Cross-caps are adequate there, then they are adequate in the treble.
If you want to improve the treble you will have to improve the midrange, because human hearing automatically allocates its priority to the midrange.
When the midrange is improved, the bass and treble sound better, unless compromised by lower quality drivers or crossover components.
Get the midrange right as priority in allocating Budget, and then get the treble and bass to blend with the mids by using similar quality components.
Jantzen Z-Superior in both mids and treble will cause greater coherence than Z-Silver in one and Cross-Cap in the other.
Ideally the bass should have the same capacitor model also, but that will be very expensive with Z-Superior, and for little audible gain over Cross-Cap there.
You have now missed the 20% discount sale on Sonicaps, for which you could have got Jantzen Z-Superior quality in slightly different sound for lower price, and available in a wider selection of values so that you could have bought the optimum cap values for those drivers without having to connect parallel pairs or triples of Z-Superior, as you will eventually realize you will have to do if you want better than Cross-Cap {which originally given your specification I thought you did}.
You could have used your existing 66 crossover for mids and treble with Sonicaps installed, and bought lower DCR Solen or Jantzen AIR core inductors for the bass filter to allow greater bass level and somewhat faster bass sound.
You can still do this.
If you do not receive the copies of the measurements you paid for, and an offer to exchange non-optimum choice, poorly advised, components for same total price better type allocation components for your purpose, then demand a refund for the crossovers and send them back,
BUT, do not decide about any values of capacitance and inductance till you see all the measurements that were done.
I recommend that you ask for the measurements first.
If those are not sent to you, then send the entire crossovers back and demand refund for the prices of the board and parts.
You are legally entitled to that {unless you have given away you rights as result of some peculiar agreement}.
I have to go now. This is taking a very long time, and I think it likely that I have not addressed all your concerns.
I can better do that if I can see all the measurements that you were told were made, because then you can see what I am describing.
{Most people trust there eyes more than their ears, but I don't.}
Last edited:
Hi Alan,
To do the experiments it will be easier if I replace the wiring so I can locate the cross-over on the bottom of the cabinet behind the ABR. Is the length and type of wire critical?
Here are a couple of examples of easily available cable:
flat type: High Performance Flat OFC Speaker Cable | Dick Smith Online Shopping
fig 8 type: Heavy Duty Fig 8 Speaker Cable - Jaycar Electronics
I'll also use screw terminal strips so I can easily remove the crossovers and change components. Would these affect the listening tests?
DG
To do the experiments it will be easier if I replace the wiring so I can locate the cross-over on the bottom of the cabinet behind the ABR. Is the length and type of wire critical?
Here are a couple of examples of easily available cable:
flat type: High Performance Flat OFC Speaker Cable | Dick Smith Online Shopping
fig 8 type: Heavy Duty Fig 8 Speaker Cable - Jaycar Electronics
I'll also use screw terminal strips so I can easily remove the crossovers and change components. Would these affect the listening tests?
DG
Hi Alan,
I did ask John for copies of all of the graphs/plots previously described. I received 2 e-mails which I have attached.
It doesn't look as if I am going to get very much further by making requests to John. I have also attached the initial e-mail I sent to him requesting the additional information. You will see that although I commented on the responsibility of payment for any substitute components, he did not mention it in his replies. He tells me that the Time Domain plots are transient and would not be of any use to me anyway. Come to your own conclusions!
I'm not sure where I go from regarding any redress from (Audio Components (UK) ltd.). But I do not intend to continue to publish or even get involved in anymore of the 'I said','he said' rhetoric.
What I need to do is to move forward from this point. I can't see if my sending bask the crossovers is going to result in any form of refund. You mention that members of this forum have previously had issues with unsatisfactory work, either with Audio Components (UK) ltd. or any other technical service provider. Not wishing to know any details of these events I just wondered what the eventual outcome was? I'm not sure where I stand legally.
So, moving on, I need to outline a methodology for making improvements to my new crossovers. This is taking into account my lack of any specialised testing equipment, saving my new multi-meter, which is not breathtakingly accurate.
Best Regards
Wayne
the Plots and the Components, and legalities, etc ...
Hi Wayne,
yes, you had previously posted the Impedance Plots that are again in #704.
I agree, that Time Domain plot is not of much use as neither of use have the computer program required to decipher it.
I was hoping he had a different type of time domain plot, a CSD - Cumulative Spectral Display -{ also commonly known as Waterfall Plot}-,
because on that the resonances are visible.
CSD can be made from the same test signal that is used for SPL mag, etc ...
but I do not know if his Praxis can do those.
I would be very surprised if he cannot do a CSD, because those can be done from other programs quite easily ...
lots of diyers have bought suitable programs, and nearly all the professional designers do them from fairly simple programs.
You are entitled to the plots you paid for for the SEAS tweeters you bought, and for your mid-domes.
He would have to have done plots of both SPL versus Frequency and Impedance versus Frequency for the SEAS tweeter or he would not have been able to have the computer calculate the components for the crossover.
He should have labelled each MD to identify which from which, because you did pay for both to be measured, thus you can request identification of each,
but first if no other plots are soon sent, ask again for those ... including SPL mag and Impedance/Phase for the SEAS.
Don't push for the Off-Axis plots if they are not sent ... we can survive without those.
Vertical Off-Axis plots are the most useful ones when designing crossovers.
There is sufficient in sba's earlier posted Horizontal off-axis for the MDs for me to know where they can be optimally crossed,
and SEAS off-axis plots are usually close enough to accurate,
{and also their on-axis plots, thus why I am suspicious of that C9,L6,R1 network across the tweeter. I can guess why he has put it there, but I prefer to see the raw measured tweeter to be sure}.
Acknowledge to him that Time Domain type is not needed now.
If you want to, then say you had thought it would be a Cumulative Spectral Display plot ... if he's interested he will comment about that.
Regarding Legal Redress:
I recommend that you enquire at the relevant Government office about Consumer Rights for exchange or refund if the Product or Service you paid for was not what you received.
A lot of people are apathetic and do not enquire, nor demand their legal rights, and PERHAPS -{and I do mean "perhaps"}- "John" is thinking that you may do the same.
He is in Business, thus he does know the Law ... or he should, and he is being lax if he doesn't.
You do have a case, because no-one who requested a modern crossover be designed would expect to receive one with a greater than 1 octave wide dip with a maximum of -6dB at its centre.
{Actually, it -7dB with respect to the mid's level, and -5dB with respect to the tweeter level, thus why I previously stated it as "average of -6dB maximum".}
Thus the actual manufactured crossover you received does not work to anywhere near the degree of your expectation, nor even to the specification he implied in his original report to you.
As such, you are entitled to exchange for one that does, or refund.
{I acknowledge here that it is fortunate you did not have any of your old inductors installed on the new board, because at the very least an Order can be issued for him to refund you for the cost of all parts and assembly of that crossover if he will not agree to do anything else.}
You are not likely to easily get refund for the time spent measuring the drivers, but I assure you that a good lawyer would get such back also,
however that will likely cost you more than your outlay to date, thus simply enquire first the Consumer Law entitlement and decide what to do based on the advice you are given there.
Regarding the second Simulated plot for the change to 0.6mH and 6.1uF:
This is moved in the right direction, but is not yet far enough.
I can specify what to simulate next for what I think will be close to the optimum for the non-notched MD, and from the results of that I can calculate what mH and uF will be required to get the notched MD better towards the other's response.
After that there will have to be simulations done for changes to the treble filter so that the tweeter will add with the mids for flat response.
I emphasize here, there is only ONE frequency location where the two MDs can be made to get as close to match as is possible with a simple crossover and no large audible compromise, and for that frequency the tweeter filter will have to be changed also.
If it transpires that "John" interested to continue till you are satisfied, then I'll describe how to do the above, but decide that based on his response to your request for the drivers' plots.
"Satisfied" in this case cannot include Perfect, it can only include what is possible with the MDs,
though it can include exchange of the electro caps and P-cores in the bass filter if he stated that those were of suitable quality to match the mids' Cross-caps and air-core inductors, and Z-Silver caps in the treble -{latter which you don't need and will have to change, and similarly the C9,L6,R1 components}.
What I stated was:
"I know of one case of Scanspeak mid substituted into a 66 by Audio Components that was not a success,
however I can say no more about that because I think the matter may not yet be resolved, and I do not know at this time."
This is currently still the case.
Hi Wayne,
yes, you had previously posted the Impedance Plots that are again in #704.
I agree, that Time Domain plot is not of much use as neither of use have the computer program required to decipher it.
I was hoping he had a different type of time domain plot, a CSD - Cumulative Spectral Display -{ also commonly known as Waterfall Plot}-,
because on that the resonances are visible.
CSD can be made from the same test signal that is used for SPL mag, etc ...
but I do not know if his Praxis can do those.
I would be very surprised if he cannot do a CSD, because those can be done from other programs quite easily ...
lots of diyers have bought suitable programs, and nearly all the professional designers do them from fairly simple programs.
You are entitled to the plots you paid for for the SEAS tweeters you bought, and for your mid-domes.
He would have to have done plots of both SPL versus Frequency and Impedance versus Frequency for the SEAS tweeter or he would not have been able to have the computer calculate the components for the crossover.
He should have labelled each MD to identify which from which, because you did pay for both to be measured, thus you can request identification of each,
but first if no other plots are soon sent, ask again for those ... including SPL mag and Impedance/Phase for the SEAS.
Don't push for the Off-Axis plots if they are not sent ... we can survive without those.
Vertical Off-Axis plots are the most useful ones when designing crossovers.
There is sufficient in sba's earlier posted Horizontal off-axis for the MDs for me to know where they can be optimally crossed,
and SEAS off-axis plots are usually close enough to accurate,
{and also their on-axis plots, thus why I am suspicious of that C9,L6,R1 network across the tweeter. I can guess why he has put it there, but I prefer to see the raw measured tweeter to be sure}.
Acknowledge to him that Time Domain type is not needed now.
If you want to, then say you had thought it would be a Cumulative Spectral Display plot ... if he's interested he will comment about that.
Regarding Legal Redress:
I recommend that you enquire at the relevant Government office about Consumer Rights for exchange or refund if the Product or Service you paid for was not what you received.
A lot of people are apathetic and do not enquire, nor demand their legal rights, and PERHAPS -{and I do mean "perhaps"}- "John" is thinking that you may do the same.
He is in Business, thus he does know the Law ... or he should, and he is being lax if he doesn't.
You do have a case, because no-one who requested a modern crossover be designed would expect to receive one with a greater than 1 octave wide dip with a maximum of -6dB at its centre.
{Actually, it -7dB with respect to the mid's level, and -5dB with respect to the tweeter level, thus why I previously stated it as "average of -6dB maximum".}
Thus the actual manufactured crossover you received does not work to anywhere near the degree of your expectation, nor even to the specification he implied in his original report to you.
As such, you are entitled to exchange for one that does, or refund.
{I acknowledge here that it is fortunate you did not have any of your old inductors installed on the new board, because at the very least an Order can be issued for him to refund you for the cost of all parts and assembly of that crossover if he will not agree to do anything else.}
You are not likely to easily get refund for the time spent measuring the drivers, but I assure you that a good lawyer would get such back also,
however that will likely cost you more than your outlay to date, thus simply enquire first the Consumer Law entitlement and decide what to do based on the advice you are given there.
Regarding the second Simulated plot for the change to 0.6mH and 6.1uF:
This is moved in the right direction, but is not yet far enough.
I can specify what to simulate next for what I think will be close to the optimum for the non-notched MD, and from the results of that I can calculate what mH and uF will be required to get the notched MD better towards the other's response.
After that there will have to be simulations done for changes to the treble filter so that the tweeter will add with the mids for flat response.
I emphasize here, there is only ONE frequency location where the two MDs can be made to get as close to match as is possible with a simple crossover and no large audible compromise, and for that frequency the tweeter filter will have to be changed also.
If it transpires that "John" interested to continue till you are satisfied, then I'll describe how to do the above, but decide that based on his response to your request for the drivers' plots.
"Satisfied" in this case cannot include Perfect, it can only include what is possible with the MDs,
though it can include exchange of the electro caps and P-cores in the bass filter if he stated that those were of suitable quality to match the mids' Cross-caps and air-core inductors, and Z-Silver caps in the treble -{latter which you don't need and will have to change, and similarly the C9,L6,R1 components}.
What I stated was:
"I know of one case of Scanspeak mid substituted into a 66 by Audio Components that was not a success,
however I can say no more about that because I think the matter may not yet be resolved, and I do not know at this time."
This is currently still the case.
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The Good, The Bad, and The Ugly !
Hi Denny,
your case won't be quite like that Movie, but it may become:
The Good, The Bad, and The Mediocre
unless you are careful !
The screw terminals are a good idea.
For internal cable, I recommend that you use EXACTLY the SAME cable that you are using to connect the l'speakers to your amplifier.
If you do not have sufficient of that left, or are considering buying new for amp to speakers also, then Post here.
I have looked at the Links you posted, and I do not recommend either cable.
Better can be done for little or no greater cost, and better again for moderately higher price.
This will require a long Post, for which I do not have time remaining today,
so Post your reply to what I have stated, and I'll continue next time based on that.
Hi Denny,
your case won't be quite like that Movie, but it may become:
The Good, The Bad, and The Mediocre
unless you are careful !
The screw terminals are a good idea.
For internal cable, I recommend that you use EXACTLY the SAME cable that you are using to connect the l'speakers to your amplifier.
If you do not have sufficient of that left, or are considering buying new for amp to speakers also, then Post here.
I have looked at the Links you posted, and I do not recommend either cable.
Better can be done for little or no greater cost, and better again for moderately higher price.
This will require a long Post, for which I do not have time remaining today,
so Post your reply to what I have stated, and I'll continue next time based on that.
Last edited:
Hi Alan,
I have attached my latest exchange of e-mails with John, even though I said I wouldn't post e-mail messages!
I think you'll find that in his final reply to me (the top entry being the most recent) he could not propose a better service for me. He is going to send me the new components he specified which I will fit to the crossovers. He later proposes a home visit if that does not work!
I can't really ask for anymore. But, before his visit I will need to know the details you have (and are) proposing. So I need to really get up to speed with the technical side in order to make his visit successful.
You mentioned that the new proposals from John were in the right direction, but not enough! You also mentioned you could see why he introduced the new parallel circuitry bridging the new Seas tweeters. Could you please explain that to me. I will of course arm myself with the right questions in order to get the answers we need. I hope this can be done using our Forum correspondence.
By the way, I don't think I will keep pestering John with requests for plots. I think it's best if take the route I have outlined. I just need to get to grips with the complexities of crossover circuitry (as best I can).
What do you think?
Best Regards
Wayne
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to Wayne Swann
Hi Wayne,
look at the top-right corner of this page and find the "Private Messages".
It will be under your name there.
Click on that to open. I have sent you a message there.
Here are two information sources in case you need such later.
Click on these to open:
The Office of Fair Trading
Consumer Direct
There are a few others also, but the above can be a useful start.
Hi Wayne,
look at the top-right corner of this page and find the "Private Messages".
It will be under your name there.
Click on that to open. I have sent you a message there.
Here are two information sources in case you need such later.
Click on these to open:
The Office of Fair Trading
Consumer Direct
There are a few others also, but the above can be a useful start.
Last edited:
Internal wiring, and cables
Hi Denny,
as you are in Australia, I ask:
is your now not available loudspeaker cable one of the two original types made to Matthew Bond's specification for his Tara Labs brand when he started in Australia ?
If you have any of either of those, and in particular his second model, then do keep it !
I expected that the conventional established restorer companies would recommend 79 strand, or similar, because those companies cater mostly to conservative customers who will not buy something unless it has been accepted in use for a long time
... and that is fair enough for listeners who do not devotedly follow Hi-Fi developments,
however a lot more has been established by reliable hearers since the introduction of the original 79 strand and the later OFC variations.
Most of the restorers do not study Physics nor advanced Electronics/Communications, etc ... thus can not be expected to fully understand how wire, particually in a Cable format, can behave with wide-band AC signals.
It is a complex subject, and I do not know it all myself, and I will not be posting at length about it here, except sufficient to support my earlier statement and other recommendations I will make later when I have more time available.
The original wiring in the 66s is highly unlikely to be silver plated copper.
It is most likely Tin plated copper, and that is good, because tin is the metal in the largest proportion in the solder alloys used for audio components.
Tin containing solder will attach well to a tin surface,
and if I remember correctly, such solder electrically better connects to tin than to copper.
I recommend the tin plated wire be left in the 66s, unless a substantially better type is going to be used for loudspeaker to amp,
and then put that in the 66s also.
Do you prefer to place the crossovers lower in the cabinet, thus need longer internal wire Denny ?
rather than place them higher in the cabinet as Wayne has done ...
Silver plated copper wire was not invented by an Audio specialist.
It was made for another reason {the specific I have forgotten}, and adopted by sellers of audio cables who thought they could sell it on the basis of silver being a {slightly} better conductor than copper, and that audio enthusiasts were becoming aware of Skin Effect
{high frequencies being carried in the outer section of the wire's diameter},
thus silver plated copper could be marketed as better for conduction of treble !
Well, as can be heard be critical listeners, there is an audible difference between copper wire and silver plated copper wire,
and there is also audible difference again if entirely silver wire is used ...
... but which conveys the signal with the least change to the signal ?
I think Silver may, if it remains uncontaminated on its surface under the insulation, though copper if it remains uncontaminated under the insulation would not likely be far behind, if behind at all other than being of slightly higher electrical resistance.
I currently can't think of why silver plated copper could work as well as either metal can alone for Audio Frequencies, but ... ?
I think a better conveyer of audio signals is hollow wire, because then there very little Skin Effect.
Yes, there are a few companies with hollow wire cable products, and such are expensive, justifiably because hollow wire is more difficult to manufacture, and to maintain unsquashed !
... and one would have to keep it unsquashed at home if its benefits are to remain.
The enthusiast Linn listeners like Linn cable, and likely Linn do use it inside their l'speaker enclosures also,
thus continuity of signal transmission in same medium, which I think is valid, even if only small in audibility it is worthwhile if one is a critical listener.
Thus my earlier posted statement.
I will return in a few days time, but do post follow-up comments here in the interim.
Hi Denny,
as you are in Australia, I ask:
is your now not available loudspeaker cable one of the two original types made to Matthew Bond's specification for his Tara Labs brand when he started in Australia ?
If you have any of either of those, and in particular his second model, then do keep it !
I expected that the conventional established restorer companies would recommend 79 strand, or similar, because those companies cater mostly to conservative customers who will not buy something unless it has been accepted in use for a long time
... and that is fair enough for listeners who do not devotedly follow Hi-Fi developments,
however a lot more has been established by reliable hearers since the introduction of the original 79 strand and the later OFC variations.
Most of the restorers do not study Physics nor advanced Electronics/Communications, etc ... thus can not be expected to fully understand how wire, particually in a Cable format, can behave with wide-band AC signals.
It is a complex subject, and I do not know it all myself, and I will not be posting at length about it here, except sufficient to support my earlier statement and other recommendations I will make later when I have more time available.
The original wiring in the 66s is highly unlikely to be silver plated copper.
It is most likely Tin plated copper, and that is good, because tin is the metal in the largest proportion in the solder alloys used for audio components.
Tin containing solder will attach well to a tin surface,
and if I remember correctly, such solder electrically better connects to tin than to copper.
I recommend the tin plated wire be left in the 66s, unless a substantially better type is going to be used for loudspeaker to amp,
and then put that in the 66s also.
Do you prefer to place the crossovers lower in the cabinet, thus need longer internal wire Denny ?
rather than place them higher in the cabinet as Wayne has done ...
Silver plated copper wire was not invented by an Audio specialist.
It was made for another reason {the specific I have forgotten}, and adopted by sellers of audio cables who thought they could sell it on the basis of silver being a {slightly} better conductor than copper, and that audio enthusiasts were becoming aware of Skin Effect
{high frequencies being carried in the outer section of the wire's diameter},
thus silver plated copper could be marketed as better for conduction of treble !
Well, as can be heard be critical listeners, there is an audible difference between copper wire and silver plated copper wire,
and there is also audible difference again if entirely silver wire is used ...
... but which conveys the signal with the least change to the signal ?
I think Silver may, if it remains uncontaminated on its surface under the insulation, though copper if it remains uncontaminated under the insulation would not likely be far behind, if behind at all other than being of slightly higher electrical resistance.
I currently can't think of why silver plated copper could work as well as either metal can alone for Audio Frequencies, but ... ?
I think a better conveyer of audio signals is hollow wire, because then there very little Skin Effect.
Yes, there are a few companies with hollow wire cable products, and such are expensive, justifiably because hollow wire is more difficult to manufacture, and to maintain unsquashed !
... and one would have to keep it unsquashed at home if its benefits are to remain.
The enthusiast Linn listeners like Linn cable, and likely Linn do use it inside their l'speaker enclosures also,
thus continuity of signal transmission in same medium, which I think is valid, even if only small in audibility it is worthwhile if one is a critical listener.
Thus my earlier posted statement.
I will return in a few days time, but do post follow-up comments here in the interim.
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I have been aware of this thread for some time although I have not read the more recent posts but if anyone wants a pair of MF500 2" Domes from Celestion 66s then there seems a genuine pair on the Australian eBay site under the "vintage speaker" section........(hope I'm not duplicating a previous post)
Merry Xmas, Jonathan
Merry Xmas, Jonathan
to Jonathan Bright
Hi Jonathan,
thankyou for notifying us of the MF 500s for sale.
The asking price is very high for such old drivers.
They would need to be in very good condition to be worth anything towards that amount of money, versus buying new modern drivers.
I will watch to see how high the offers go before the listed end time of that sale.
I see you have started some interesting looking threads.
I hope to have time some time before too long in 2011 to join the discussion in at least one of them
... and whatever in the others that I have not read yet, which is most of them ...
Hey, you are a Wodehouse reader !
My father was one, and regularly quoted from such.
Best wishes for the New Year to you, and to whoever else may be reading here before then.
***************
To Wayne Swann,
I will return with more comments about wiring for drivers when I have time available, but look now for a follow-up private message.
{I have notification of any to me sent to my email address.}
Hi Jonathan,
thankyou for notifying us of the MF 500s for sale.
The asking price is very high for such old drivers.
They would need to be in very good condition to be worth anything towards that amount of money, versus buying new modern drivers.
I will watch to see how high the offers go before the listed end time of that sale.
I see you have started some interesting looking threads.
I hope to have time some time before too long in 2011 to join the discussion in at least one of them
... and whatever in the others that I have not read yet, which is most of them ...
Hey, you are a Wodehouse reader !
My father was one, and regularly quoted from such.
Best wishes for the New Year to you, and to whoever else may be reading here before then.
***************
To Wayne Swann,
I will return with more comments about wiring for drivers when I have time available, but look now for a follow-up private message.
{I have notification of any to me sent to my email address.}
Last edited:
Hi i thought i'd post here instead of the ditton 44 thread as this seems like it has more life in it.
I have recently bought a very cheap pair of 44's cheap mainly because the tweeters had been badly replaced, with a rather large hole cut to accomodate them.
So i decided to renovate them as follows, i replaced the tweeters with the seas recommended here with a 1r resistor in series and a 10r in paraell which had been listed as optimum on another site. I also recapped the crossover's with jantzen mkt caps for the treble and mid and electro's for the bass, but now the sound i lifeless with no detail and the soundstage is very closed in. Also i should mention that the cabinet around the tweeter is no yet properly sealed due to christmas post.
I am after any advise with this, could the resistors be the wrong value, could it be a lack of esr simulating resistors or is it the mkt caps that just ar'nt very good.
thanks
chris
I have recently bought a very cheap pair of 44's cheap mainly because the tweeters had been badly replaced, with a rather large hole cut to accomodate them.
So i decided to renovate them as follows, i replaced the tweeters with the seas recommended here with a 1r resistor in series and a 10r in paraell which had been listed as optimum on another site. I also recapped the crossover's with jantzen mkt caps for the treble and mid and electro's for the bass, but now the sound i lifeless with no detail and the soundstage is very closed in. Also i should mention that the cabinet around the tweeter is no yet properly sealed due to christmas post.
I am after any advise with this, could the resistors be the wrong value, could it be a lack of esr simulating resistors or is it the mkt caps that just ar'nt very good.
thanks
chris
Speaker internal wiring / spkr wiring
I did post this reply before but it's gone now! There also is a problem in the 'quote' software as the wrong post is inserted so there is no quote included here but this is a response to one of Alan's previous posts.
Hi Alan,
The amp to speaker cables are not the ones you mention. The ones I use at present were purchased already made up with connectors and I can't recall the brand of cable. It is thick and relatively inflexible and so would be difficult to use even if I could source it. I've various other cables but not enough to use for both tasks. I'll need to choose a cable so any help on this would be welcome.
The idea is to put the crossovers on the base behind the ABR for ease of access and so to crossovers can be removed and modified easily. I replaced the original cable with stripped down Audioquest? cables when I replaced the capacitors (the thinner type not the thick type). The original cable looked rather thin, a bit like hook-up wire.
My only experience with Linn and cables was in the 1980's when I had a couple of amplifiers on trial at home. My memory is a little hazy on this but I do recall that one amp was a little Linn that was well reviewed and the sound from it was highly dependent on the speaker cable. It was not good sounding with any of the cables I had on hand. Each cable resulted in a different sound. Could it be that they want you to buy their own cable?
DG
I did post this reply before but it's gone now! There also is a problem in the 'quote' software as the wrong post is inserted so there is no quote included here but this is a response to one of Alan's previous posts.
Hi Alan,
The amp to speaker cables are not the ones you mention. The ones I use at present were purchased already made up with connectors and I can't recall the brand of cable. It is thick and relatively inflexible and so would be difficult to use even if I could source it. I've various other cables but not enough to use for both tasks. I'll need to choose a cable so any help on this would be welcome.
The idea is to put the crossovers on the base behind the ABR for ease of access and so to crossovers can be removed and modified easily. I replaced the original cable with stripped down Audioquest? cables when I replaced the capacitors (the thinner type not the thick type). The original cable looked rather thin, a bit like hook-up wire.
My only experience with Linn and cables was in the 1980's when I had a couple of amplifiers on trial at home. My memory is a little hazy on this but I do recall that one amp was a little Linn that was well reviewed and the sound from it was highly dependent on the speaker cable. It was not good sounding with any of the cables I had on hand. Each cable resulted in a different sound. Could it be that they want you to buy their own cable?
DG
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